Method of and system for taking X-ray photographs



H. FRANKE July 4, 1933.

METHOD OF AND SYSTEM FOR TAKING X-RAY PHOTOGRAPHS Filed Feb. 5, 1931 2 Sheets-Sheet 1 July 4, 1933. H. FRANKE 1,917,108

I METHOD OF AND SYSTEM FOR TAKING X-RAY PHOTOGRAPHS Filed Feb. 5, 1931 2 Sheets-Sheet 2 Patented July 4,1933

PATENT OFFICE. i

FRANZ-RE, 0F HAMUR G -ALTONA, GERMANY, ASSIGNOR TO G. H. F. MllLLER AKTEENGESELLSOHAFT, 02F HAMBURG--FUHIISBUTTEL, GERMANY, A CORPORATION METHOD AND SYSTEM FOR TAKING X-RAY PHOTOGRAPHS Application filed February 5, 1931, fierial li'o. 5i'-3;6fi', and in Germany December 2, 1929.

My invention relates to improvements in the method of and system for taking X-ray photographs, and more particularly 1n the method and system described in my copend at the rear of the box containin the sensitized film or plate, and the exposure is interrupted when the instrument shows 11 value corresponding to the most favourable blackening of the plate. hen making the exposure a be must be used the rear wall of which is provided with a hole permitting the passage of the X-inys intended to act on the cell. In some cases and particularly when taking a photograph of a reclining patient the patient is inconvenienced by disposing the cell at the rearof the box.

One 0 the obj ects of the improvements is to provide a method and a system in which an ordinary box may be provided, and in which the said box may be disposed so that it does not inconvenience the patient, and with this object in view my invention consists in disposing the said cell in a part of the rays emanating from the tube which are directed laterally of the object being photographed, and placing a filter between the tubeand the said cell,

which has the same absorption us the object. 'I'have discovered that with sulficient accuracy, a filter of a thickness corresponding to the thickness of the object may be employed.

When using the method described in my aforesaid application for patent, the most favourable time of the exposure mainly depends on the degree of the absorption of the rays by the object.

If the said object has a high absorbing power, the X-ray tube must be under load for along period of time for obtaining the most favourable blackening of the sensitized plate.

Another object of the improvements is to provide menus for preventing overloading of the tube, "and with this object in view I provide a safety device comprising time controlled mechanism for automatically opening the circuit of the tube when or before the highest permissible time of operation of the tube has been attained. By means of this safety device injury to the tub'ebyroverload prevented even if an object of high absorbing power is radiated. In carrying out this part of my invention I connect the-safety device with the aforesaid measuring instru-' ment comprising a cell sensitive to radiation, the said instrument operating a relay after the highest permissible time of exposure for arresting the time controlled mechanism.

, For the purpose explaining the invention several examples embodying the some have been shown in the accompanying drnwings in which the same reference characters have been used in all the views to indicate corms xmding parts. In said drawings,

Fig. l is a diagram of elevation showing my improved system,

Fig. 2 is a detail plan view on an enlarged scale showing the sensitive cell and the filter covering the same, and i Fig. 3 is a diagram similar to the one illustrated in Fig. 1 and showing a modification and in addition a time controlled mechanism connected with the measuring instrument.

In the example shown in Figs. 1 and 2 the system comprises an ionirnetric measuring instrument similar in construction to the one described in the above-mentioned application for patent. The said instrument comprises a sell or chamberl which is sensitive to radiation, and which as shown is in the form of a thimble. The insulated electrode 2 of the said cell 1 is connected with an electrometrio indicating device 3, and the jacket 4. of the cell providing the other electrode is grounded.

The insulated electrode 2 of the said ionimetric system is connected with one terminail of an electrostatic machine '5 the other terminal of which is grounded. Thereby a negative charge is imparted to the electrode 2 the potential of which can beread from i Further, the electrode neirof 50 the other ter- X-rays imv et en ififiven ionizatt" "coi -h ir d a nus tient 9 lying on a table8 and the l l son or: a

" 'simiiartojthe sys- Odi Iw'hieh is 7 located on the table 1Q 9and inapencil the tube tsnd" (1i i "the Imyt -T r I thenisa "w u i-s .i were BQQ 3 f '1, en 3 m-qsneeema 138 :1853

in m'y fl' f he r the mark as is h the ahsorntion ,4 patient 9 is determined by fi 'l'p'eamlzoie instrument For this pure, pose part of the body of to h'e is'aee ertained by It may be found foreximpiethat a eeaniumexpoeed from the 1i germane-finer ofan v off suitable' (J lhyyli'flehd e with one termi- 1 fi teea atmesreeenhe etmer of electricity 519 s ix 5; ienetion oft e 1,917,108 n or aluminium plate of a thickness of two mil- 25-] imeters or a cranium exposed from th w front'si e to an aluminium filter of a nessof three millimeters. Therefore" an alts minim late 11 'W e (is to the W tihn'coeflihient of the body andetheem f represents the absorption of the said y The said plate is placed on the late-mid sefithhainminium plates seein s 5, sorption coeflieient corresponding to'the co-; eficient of the objectpreviously ascertained? be -superimposed? The cell 1 is placedon the tahie bfllowge filter 12. edla a ma' eexposureain 'inpfm; of thefbeam z rays emanatingzfrom"fiie X-ray tube "7. is directed through the 9 and ear the sensitized pi tmconfined thebox 10, while the cello L is radiated lateral; portion of .of rega -high portion'first passes-through the platell. The cell 1 to the substantially the samemrgy of in the system in its placed iltotb fieldpf the median PQMQ of the'pencil at W t rays'i-passing throughtheyatient 7'9 and j 110x10 and at the rear of the patient andthtl' i box,becausethealuminiumplate1l isequi lent teilie patient 9 with referenoeto the t. r; sorption coeflicient. v v i i one After emrgizing the tube! theelectmmefipii. 3 is observed, and when the hand thereof s cometo the pointwhich'before has been V j by calibrating the sensitized plate, for exani-f plerwhen its hand arrives on the fourthseale'lee marktheexposure is interrup ed. y the electromiter 3;indicateshth time tempting t e exposure w ic corres tothe most favourable blackening of theeelie sitizedpilate 4 In the modification shown in Fig. 3 vMeonneeted with an alternating curnent sup: ply eiieiiit 14 are connected with the lb-of awoitage the secondary IQ of whmi is, connected with a glowiag cathode- U3 xnmebe 17. The rays emanating from the 7 it; tuhe'fl? pass. through the object 18 and in}? I pingeanfpon the sensitized-plate or filmcone; tained in the ,box 19. In the path ofthe'rgys A, of the time 17 and at the rear of thepbject and the'box 19 thereis an ionimetric cell 20, I the insulated electrodeBLof which smnected with an eleetrometrie strum'ent 22. while the jicket 23 the'celi providing the other electrode is grounded. The electrode 2170f thesaitl iommetritsys tem is connected with one terminal of an F e j trostatie machine 24 the other which is grounded, the said eIectro-static ma;- chine imparting anegative charge tothe'in suleted electro e 21 the volt of whichl 1; .1 1 read from the scale 25 of the e ectrometer 22. f Further-the electrode 21 is connected by aleail: 26 with one terminal of a rotary condenser- 51, the other terminal of which is grounded 1 0 lf niow the charged ionization cell 20 is exdevice comprises a time controlled mccha cell is ionized, and a part of the electric thereof is removed which corresponds to the energy of the radiation, so that the in dilation of the elcctrometer 22 falls oil in acmce with the amount of electric charge movedand the capacity of the system.

-Whenusing the ionimetric measuring indnlmentby means of the said instrument at Edi sensitized plate of the character of the plate to be used in the exposure is calibrated in the manner described in my aforesaid appfidionfor patent. For making the exposure for example the cell and box 19 containing a sensitized plate are placed at the mar of the object l8. switching the apparatus the displac ment of the had of the electromcter is ob crved, and the me isinterrupted when the hand I! or" the said elcctrmieter has moved through the spec previously -detcrmined calibration ad has reached for example the fourth scale mtk. Therefore the electromcter indicites the time when the expos re should be Interrupted The apparatus so far described has been illustrated in my aforesaid application for patent, and it is provided ith safety device which will now be described. In the ample shown in the figures t said safety QBOf may known orpre'ferred form and en for example from a spring motor or the that.

r The hand 29 of the said time controlled apparatus is adapted to be reset and it cooperates with a contact 30 adapted to be set in any desired positionrclatively to andin contactwitha segmental rail-31 of coach. five of which carries an armature 87.

disposed concentrically in or upon the housing of the time controlled apparatus. The rail. 31 connected by a lead with. one brmiualof the coil of an lCCt-1O111Qt The hand 29 is connected by a and through a battery 33 with the other terminal of the coil of the said elect-coinage Ona stationary bearing 34 lever having two arms 35 and 36 is swivelled, the arm 35 The other arm 36 is insulated, and it carries a contact 38 cooperating with a contact The arm 36 and the contacts 88, 39 are included in the circuit 14.

If the hand -29 of the time controlled apparatus is turned so far that it engages the contact 30 the circuit including the electromagnet 32 is closed. Therefore the armature 37 is attracted and the circuit of the primary 15 is interrupted at 38, 39, so that the X-ray tube 17 is de-energized.

The electrometer 22 is provided with a segmental marginal rail l0 of conductive material and on the said rail a contact l1 is shiftable, which cooperates with the hand 27 of the electrometer. The rail 40 is connected by a lead with one terminal of the coil of an electromagnet Q and the hand 27 is connected by a lead withta battery t3 and the other terminal of the coil of the electroniagnet Ona bearing 44 mounted on the cf the electroineter 22 engages the contact 41 the circuit includingthe clcctromagnet 42 is closed, the armature 47 is attracted and the time controlled apparatus 28 is arrested by the latch 4L8 engaging the wheel 49. In lieu of the aforesaid electromagnets 32 and 4). solenoids or the like may be used.

The operation of the apparatus is as follows:

It may be assumed that the most favourable blackening of the sensitized plate isobtained when the h and 27 arrives at the scale mark of the fourth scale 25 of the electrometer. At the beginning of the radiation both hands 27 and 29 are in their zero positions. The contact 41 is on the fourth scale mark and the contact30 is brought into ,c position corre. ending to the highest permissible load of the tube. The tube 17 is now switched into the circuit by means of a switch lever (not shown in the figure), ml the time controlled apparatus 28 is rted by releasing the same from the locking: device (not shown). i

If an object 18 of exceptionally high ab sorption power is radiated it may happen that the highest permissible load of the tube is attained before the time of exposure coriespon ding to the mostfavourable blackening of the sensitized plate has passed. In my improved system the hand 29 engages the contact 30 when the said permissible load has been attained. so that in the manner d. scribed above, the tube 17 is witched out of the circuit by means of the electromagnet It may be assumed that in this case the hand 2'? has reached only the scale mark 3, when it is arrested by switching out the tube.

Now the time controlled apparatus 28 is arrested by means of the locking device, and the attcndent allows the X-ray tube 17 to cool a short period of'time, whereupon the and 29 is turned in a direction opposite to the arrow shown in the figure and set to zero and the time controlled apparatus is again started. Now radiation is continued.

Now it may be assumed that the hand 27 of the electrometer continuing its movement reaches the scale mark 4 corresponding to the time of the most favourable blackening of the sensitized plate, before the hand 29 of CERTIFICATE OF CORRECTION.

Patent No. 1,917,108. July 4, 1933.

HEINRICH FRANKE.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring cerrection as follows: Page 1, line 73, strike out the words "elevation showing"; page 3, line 92, strike out the word "fourth" and insert the same before "scale" in line 91; and that the said Letters Patent should he read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 22nd day of August, A. D. 1933.

M Jr Moore (Seal) Acting Commissioner of Patents.

CERTIFICATE OF CORRECTION.

Patent No. 1,917,108. July 4, 1933.

HEINRICH FRANKE.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, line 73, strike out the words "elevation showing"; page 3, line 92, strike out the word "fourth" and insert the same before "scale" in line 91; and thut the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 22nd day of August, A. D. 1933.

M, J9 Moores (Seal) Acting Commissioner of Patents.

oERTIEtcA'rE or CQRRECTION.

Patent No. 1,917,108. July 4, 1933.

HEINRICH FRANKE.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows: Page 1, line 73, strike out the words "elevation showing"; page 3, line 92, strike out the word "fourth" and insert the same before "scale" in line 91; and that the said Letters Patent should be read with these corrections therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 22nd day of August, A. I). 1933.

J, Moore! (Seal) Acting Commissioner of Patents. 

